全文获取类型
收费全文 | 8384篇 |
免费 | 529篇 |
国内免费 | 295篇 |
专业分类
化学 | 1817篇 |
晶体学 | 21篇 |
力学 | 284篇 |
综合类 | 153篇 |
数学 | 4065篇 |
物理学 | 764篇 |
无线电 | 2104篇 |
出版年
2024年 | 13篇 |
2023年 | 57篇 |
2022年 | 201篇 |
2021年 | 231篇 |
2020年 | 237篇 |
2019年 | 315篇 |
2018年 | 324篇 |
2017年 | 236篇 |
2016年 | 264篇 |
2015年 | 252篇 |
2014年 | 454篇 |
2013年 | 517篇 |
2012年 | 430篇 |
2011年 | 667篇 |
2010年 | 523篇 |
2009年 | 580篇 |
2008年 | 562篇 |
2007年 | 616篇 |
2006年 | 523篇 |
2005年 | 336篇 |
2004年 | 299篇 |
2003年 | 320篇 |
2002年 | 155篇 |
2001年 | 125篇 |
2000年 | 115篇 |
1999年 | 125篇 |
1998年 | 95篇 |
1997年 | 80篇 |
1996年 | 85篇 |
1995年 | 68篇 |
1994年 | 83篇 |
1993年 | 61篇 |
1992年 | 45篇 |
1991年 | 29篇 |
1990年 | 21篇 |
1989年 | 19篇 |
1988年 | 24篇 |
1987年 | 22篇 |
1986年 | 17篇 |
1985年 | 24篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有9208条查询结果,搜索用时 46 毫秒
901.
Loïc Foissy 《Advances in Mathematics》2011,226(6):4702
We consider systems of combinatorial Dyson–Schwinger equations in the Connes–Kreimer Hopf algebra HI of rooted trees decorated by a set I. Let H(S) be the subalgebra of HI generated by the homogeneous components of the unique solution of this system. If it is a Hopf subalgebra, we describe it as the dual of the enveloping algebra of a Lie algebra g(S) of one of the following types:
1.
g(S) is an associative algebra of paths associated to a certain oriented graph. 2.
Or g(S) is an iterated extension of the Faà di Bruno Lie algebra. 3.
Or g(S) is an iterated extension of an infinite-dimensional abelian Lie algebra.
902.
In this paper we use the combinatorics of alcove walks to give uniform combinatorial formulas for Macdonald polynomials for all Lie types. These formulas resemble the formulas of Haglund, Haiman and Loehr for Macdonald polynomials of type GLn. At q=0 these formulas specialize to the formula of Schwer for the Macdonald spherical function in terms of positively folded alcove walks and at q=t=0 these formulas specialize to the formula for the Weyl character in terms of the Littelmann path model (in the positively folded gallery form of Gaussent and Littelmann). 相似文献
903.
A degree 1 non-negative graded super manifold equipped with a degree 1 vector field Q satisfying [Q,Q]=1, namely a so-called NQ-1 manifold is, in plain differential geometry language, a Lie algebroid. We introduce a notion of fibration for such super manifolds, that essentially involves a complete Ehresmann connection. As it is the case for Lie algebras, such fibrations turn out not to be just locally trivial products. We also define homotopy groups and prove the expected long exact sequence associated to a fibration. In particular, Crainic and Fernandes's obstruction to the integrability of Lie algebroids is interpreted as the image of a transgression map in this long exact sequence. 相似文献
904.
In the context of non-abelian gerbes, we define a cubical version of categorical group 2-bundles with connection over a smooth manifold. We address their two-dimensional parallel transport, study its properties, and construct non-abelian Wilson surface functionals. 相似文献
905.
We introduce notions of finiteness obstruction, Euler characteristic, L2-Euler characteristic, and Möbius inversion for wide classes of categories. The finiteness obstruction of a category Γ of type (FPR) is a class in the projective class group K0(RΓ); the functorial Euler characteristic and functorial L2-Euler characteristic are respectively its RΓ-rank and L2-rank. We also extend the second author's K-theoretic Möbius inversion from finite categories to quasi-finite categories. Our main example is the proper orbit category, for which these invariants are established notions in the geometry and topology of classifying spaces for proper group actions. Baez and Dolan's groupoid cardinality and Leinster's Euler characteristic are special cases of the L2-Euler characteristic. Some of Leinster's results on Möbius–Rota inversion are special cases of the K-theoretic Möbius inversion. 相似文献
906.
Let G be a group and ?:H→G be a contracting homomorphism from a subgroup H<G of finite index. V. Nekrashevych (2005) [25] associated with the pair (G,?) the limit dynamical system (JG,s) and the limit G-space XG together with the covering ?g∈GT⋅g by the tile T. We develop the theory of self-similar measures m on these limit spaces. It is shown that (JG,s,m) is conjugated to the one-sided Bernoulli shift. Using sofic subshifts we prove that the tile T has integer measure and we give an algorithmic way to compute it. In addition we give an algorithm to find the measure of the intersection of tiles T∩(T⋅g) for g∈G. We present applications to the invariant measures for the rational functions on the Riemann sphere and to the evaluation of the Lebesgue measure of integral self-affine tiles. 相似文献
907.
Nathanial P. Brown 《Advances in Mathematics》2011,(4):1665
If N⊂Rω is a separable II1-factor, the space Hom(N,Rω) of unitary equivalence classes of unital ?-homomorphisms N→Rω is shown to have a surprisingly rich structure. If N is not hyperfinite, Hom(N,Rω) is an infinite-dimensional, complete, metrizable topological space with convex-like structure, and the outer automorphism group Out(N) acts on it by “affine” homeomorphisms. (If N≅R, then Hom(N,Rω) is just a point.) Property (T) is reflected in the extreme points – they?re discrete in this case. For certain free products N=Σ?R, every countable group acts nontrivially on Hom(N,Rω), and we show the extreme points are not discrete for these examples. Finally, we prove that the dynamical systems associated to free group factors are isomorphic. 相似文献
908.
Takahiko Yoshida 《Advances in Mathematics》2011,227(5):1914
We introduce the notion of a local torus action modeled on the standard representation (for simplicity, we call it a local torus action). It is a generalization of a locally standard torus action and also an underlying structure of a locally toric Lagrangian fibration. For a local torus action, we define two invariants called a characteristic pair and an Euler class of the orbit map, and prove that local torus actions are classified topologically by them. As a corollary, we obtain a topological classification of locally standard torus actions, which includes the topological classifications of quasi-toric manifolds by Davis and Januszkiewicz and of effective T2-actions on four-dimensional manifolds without nontrivial finite stabilizers by Orlik and Raymond. We discuss locally toric Lagrangian fibrations from the viewpoint of local torus actions. We also investigate the topology of a manifold equipped with a local torus action when the Euler class of the orbit map vanishes. 相似文献
909.
F.G. Garvan 《Advances in Mathematics》2011,228(1):241
Andrews? spt-function can be written as the difference between the second symmetrized crank and rank moment functions. Using the machinery of Bailey pairs a combinatorial interpretation is given for the difference between higher order symmetrized crank and rank moment functions. This implies an inequality between crank and rank moments that was only known previously for sufficiently large n and fixed order. This combinatorial interpretation is in terms of a weighted sum of partitions. A number of congruences for higher order spt-functions are derived. 相似文献
910.
Shinnosuke Okawa 《Advances in Mathematics》2011,(5):2869
We show that the bounded derived category of coherent sheaves on a smooth projective curve except the projective line admits no non-trivial semi-orthogonal decompositions. 相似文献